Chemical mechanical polishing method using slurry composition containing N-oxide compound

ABSTRACT

The present disclosure relates to a chemical mechanical polishing (CMP) slurry composition that provides for a high metal to dielectric material selectivity along with a low rate of metal recess formation. In some embodiments, the disclosed slurry composition has an oxidant and an etching inhibitor. The oxidant has a compound with one or more oxygen molecules. The etching inhibitor has a nitrogen-oxide compound. The etching inhibitor reduces the rate of metal and dielectric material (e.g., oxide) removal, but does so in a manner that reduces the rate of dielectric material removal by a larger amount, so as to provide the slurry composition with a high metal (e.g., germanium) to dielectric material removal selectivity and with a low rate of metal recess formation.

BACKGROUND

Integrated chips are constructed using complex fabrication processesthat form a plurality of different layers on top of one another. Many ofthe different layers are patterned using photolithography, a process bywhich a photoresist material is selectively exposed to electromagneticradiation. For example, photolithography may be used to defineback-end-of-the-line metallization layers that are formed on top of oneanother. To ensure that the metallization layers are formed with a goodstructural definition, the electromagnetic radiation must be properlyfocused. To properly focus electromagnetic radiation, a workpiece mustbe substantially planar to avoid depth of focus problems.

Chemical mechanical polishing (CMP) is a widely used process by whichboth chemical and mechanical forces are used to globally planarize asemiconductor workpiece. The planarization prepares the workpiece forthe formation of a subsequent layer. A typical CMP system comprises arotating platen covered by a polishing pad. A slurry distribution systemis configured to provide a chemical mechanical polishing slurry to thepolishing pad. A workpiece is then brought into contact with the pad,causing the rotating platen to planarize the workpiece.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates some embodiments of a semiconductor substrate withina chemical mechanical polishing (CMP) system having a slurrydistribution element configured to provide a slurry having an etchinginhibitor.

FIG. 2 illustrates some embodiments of a structure of a disclosed slurrywith an etching inhibitor comprising a nitrogen-oxide compound.

FIG. 3 illustrates a flow chart of some embodiments of a method ofperforming a chemical mechanical polishing process with a high metal tooxide removal selectivity and a low rate of metal recess formation.

FIG. 4 illustrates some additional embodiments of a disclosed chemicalmechanical polishing slurry manufacturing and delivery system.

FIGS. 5A-5G illustrates some alternative embodiments of structures of adisclosed slurry with an etching inhibitor comprising a nitrogen-oxidecompound.

FIG. 6 illustrates a flow chart of some embodiments of a method offorming a silicon germanium fin field effect transistor (FinFET)transistor using a chemical mechanical polishing process with a highgermanium to oxide removal selectivity.

FIGS. 7A-7F illustrate cross-sectional views of some embodiments of anexemplary semiconductor substrate, whereon a method of forming a SiGeFinFET according to the method of FIG. 6 is implemented.

FIG. 8 is a chart showing some embodiments of a disclosed slurry with anetching inhibitor.

DETAILED DESCRIPTION

The description herein is made with reference to the drawings, whereinlike reference numerals are generally utilized to refer to like elementsthroughout, and wherein the various structures are not necessarily drawnto scale. In the following description, for purposes of explanation,numerous specific details are set forth in order to facilitateunderstanding. It will be appreciated that the details of the figuresare not intended to limit the disclosure, but rather are non-limitingembodiments. For example, it may be evident, however, to one of ordinaryskill in the art, that one or more aspects described herein may bepracticed with a lesser degree of these specific details. In otherinstances, known structures and devices are shown in block diagram formto facilitate understanding.

Germanium has been widely studied as a means to improve the performanceof integrated chips because it offers a high electron mobility. Oneapplication of germanium in modern integrated chip design is in finfield effect transistor (finFET). To develop a silicon-germanium (SiGe)finFET, a chemical mechanical polishing (CMP) process may be used toremove excess germanium from a surface of a substrate.

Typical CMP processes performed during the formation of a SiGe finFETmay use a slurry comprising hydrogen peroxide. Such a slurry can give ahigh germanium to oxide removal selectivity that acts to remove excessgermanium without removing oxide. However, such a slurry also formsrecesses within the germanium channel regions of the finFET device. Suchrecesses make the resulting thickness of the germanium channel regions,causing poor device performance. Therefore, a CMP process that uses aslurry having a high germanium to oxide removal selectivity and a lowrate of germanium recess formation is desirable to achieve good deviceperformance.

Accordingly, the present disclosure relates to a chemical mechanicalpolishing (CMP) slurry composition that provides for a high metal todielectric material selectivity along with a low rate of metal recessformation. In some embodiments, the disclosed slurry compositioncomprises an oxidant and an etching inhibitor. The oxidant comprises acompound having one or more oxygen molecules. The etching inhibitorcomprises a nitrogen-oxide compound. The etching inhibitor reduces therate of metal and dielectric material removal, but does so in a mannerthat reduces the rate of dielectric material (e.g., oxide) removal by alarger amount, so as to provide the slurry composition with a high metal(e.g., germanium) to dielectric material (e.g., oxide) removalselectivity and with a low rate of metal recess formation.

FIG. 1 illustrates a side view of some embodiments of a chemicalmechanical polishing (CMP) tool 100 having a slurry distribution element120 configured to distribute a slurry 122 that achieves a chemicalmechanical polishing (CMP) process with a high metal to dielectricmaterial removal selectivity (i.e., a ratio of an amount of metalremoved to an amount of dielectric material removed) and a low rate ofmetal recess formation.

The CMP tool 100 comprises a polishing pad 102 configured to performpolishing of a semiconductor substrate 112. The polishing pad 102 islocated on a platen 104, which rotates the polishing pad 102 about anaxis of rotation 106 during operation of the CMP tool 100. A padconditioning element 108, comprising a diamond grit conditioning pad, isconfigured to push on the polishing pad 102 with a downward force thatbrings the plurality of diamond particles into contact with thepolishing pad 102. As the polishing pad 102 is rotated by the platen104, the diamond particles roughen the surface of the polishing pad 102to provide for improved mechanical polishing.

The CMP tool 100 further comprises a workpiece carrier 110. Theworkpiece carrier 110 is configured to house the semiconductor substrate112 in an upside down position so that a top surface of thesemiconductor substrate 112 faces the rotating polishing pad 102. Theworkpiece carrier 110 is operable to bring the semiconductor substrate112 into contact with the rotating polishing pad 102. By bringing thesemiconductor substrate 112 into contact with the rotating polishing pad102, polishing of the semiconductor substrate 112 is performed.

The semiconductor substrate 112 comprises a semiconductor body 114 aswell as an overlying dielectric material layer 116 (e.g., oxide) and anoverlying metal layer 118. In some embodiments, the semiconductor body114 may comprise silicon, germanium, a III-V semiconductor material(i.e., comprising a combination of one or more group III elements withone or more group V elements), or some other semiconductor material. Thedielectric material layer 116 and the metal layer 118 share a commoninterface that faces the rotating polishing pad 102. In someembodiments, the metal layer 118 may comprise germanium, while in otherembodiments, the metal layer 118 may comprise other metals (e.g.,copper, aluminum, etc.). In some embodiments, the dielectric materiallayer 116 may comprise silicon dioxide, while in other embodiments, thedielectric material layer 116 may comprise other dielectric materials(e.g., SiCO).

A slurry distribution element 120 is configured to deposit a chemicalmechanical polishing slurry 122 onto the polishing pad 102. The chemicalmechanical polishing slurry 122 comprises an oxidant and an etchinginhibitor. The oxidant comprises a compound having one or more oxygenmolecules (e.g., hydrogen peroxide, potassium peroxydisulfate, etc.).The etching inhibitor comprises a nitrogen-oxide compound. The nitrogenoxide compound may have a chemical formula of R1R2R3N⁺—O⁻, wherein R1 isa first substituent, R2 is a second substituent, and R3 is a thirdsubstituent. The nitrogen-oxide compound reduces the rate of metal anddielectric material (e.g., oxide) removal, but does so in a manner thatreduces the rate of dielectric material removal by a larger amount, sothat the slurry 122 provides for a CMP process having a high metal(e.g., germanium) to dielectric material removal selectivity and with alow rate of metal recess formation. In other words, the slurry 122provides for a CMP process that removes a greater thickness of the metallayer 118 than the dielectric material layer 116, while causing a lowrecess in the metal layer 118. In some embodiments, the disclosed slurry122 may provide for a removal of the metal layer 118 and the dielectricmaterial layer 116 having a selectivity that is greater than or equal to30 (i.e., removed metal thickness/removed dielectric materialthickness>30).

It will be appreciated that in some embodiments the disclosed slurry 122may comprise additional components. For example, the slurry 122 maycomprise a surfactant (e.g., polyethylene glycol) configured to lowerthe surface tension of the slurry 122. In other embodiments, the slurrymay comprise abrasive particles that are used in mechanical polishing ofthe semiconductor substrate. For example, the slurry 122 may compriseabrasive particles comprising colloidal silica, fumed silica, aluminumoxide, silica shell based composite submicron particles. In otherembodiments, the slurry 122 may be abrasive free (i.e., the slurry 122does not comprise abrasive particles).

FIG. 2 illustrates some embodiments of a chemical structure 200 of adisclosed slurry with an etching inhibitor 202 comprising anitrogen-oxide compound.

As illustrated by chemical structure 200, the slurry comprises anetching inhibitor 202 and an oxidant 204. The oxidant 204 comprises oneor more oxygen molecules. In various embodiments, the oxidant 204 maycomprise hydrogen peroxide, potassium peroxydisulfate, ammoniumperoxydisulfate, sodium peroxydisulfate, potassium peroxymonosulfate,peracetic acid, or tert-butyl hydrogen peroxide, for example.

The etching inhibitor 202 comprises a nitrogen-oxide compound having thechemical formula of R1R2R3N⁺—O⁻, wherein R1 is a first substituent, R2is a second substituent, and R3 is a third substituent. In someembodiments, the nitrogen-oxide compound comprises a nitrogen (N)molecule bonded to an oxygen (O) molecule. In some embodiments, theetching inhibitor 202 may comprise first and second substituents, R1 andR2, comprising a chain of between approximately 1 and 20 carbon alkylsubstituents and a third substituent R3 comprising a chain of betweenapproximately 1 and 10 carbon alkyl substituents. In some embodiments,the alkyl substituent may be disposed within parent chains, while inother embodiments the alkyl substituent may be disposed within sidechains, which are carbon chains that are not in the parent chain, butare branched off from it. In yet other embodiments, the alkylsubstituent may comprise cyclic substituents.

In some embodiments, the etching inhibitor 202 may comprise pyridineN-oxide, 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO), 4-methylpyridineN-oxide, N-methylmorpholine N-oxide, 5,5-dimethyl-1-pyrroline N-oxide,trimethylamine N-oxide; quinoline N-oxide, or 2-mercaptopyridineN-oxide, for example.

The slurry may comprise a concentration of the oxidant 204 that is in arange of between approximately 10 ppm (parts per million) and 50,000 ppmand a concentration of the etching inhibitor 202 that is in a range ofbetween approximately 1 ppm (parts per million) and 10,000 ppm. Theslurry may further comprise a pH level having a range of betweenapproximately 1 and approximately 10. For example, in one embodiment aslurry composition may comprise 1,000 ppm colloidal silica, 8,000 ppmhydrogen peroxide (H₂O₂), 300 ppm 2-mercaptopyridine N-oxide, and have apH level of 6. In such an embodiment, the 2-mercaptopyridine will beformed as a passive film onto a metal (e.g., germanium) surface. Theslurry composition then operates to enable a chemical mechanicalpolishing that provides for a germanium removal rate of approximately365 angstroms/min.

FIG. 3 illustrates a flow chart of some embodiments of a method 300 ofperforming a chemical mechanical polishing process with a high metal tooxide removal selectivity and a low rate of metal recess formation.

While the disclosed methods (e.g., methods 300 and 600) are illustratedand described below as a series of acts or events, it will beappreciated that the illustrated ordering of such acts or events are notto be interpreted in a limiting sense. For example, some acts may occurin different orders and/or concurrently with other acts or events apartfrom those illustrated and/or described herein. In addition, not allillustrated acts may be required to implement one or more aspects orembodiments of the description herein. Further, one or more of the actsdepicted herein may be carried out in one or more separate acts and/orphases.

At 302, a semiconductor substrate is provided onto a platen of achemical mechanical polishing (CMP) tool. The semiconductor substratecomprises a metal region and an oxide region sharing a common interface.For example, the metal region and the oxide region may comprise adjacentregions on a top surface of a semiconductor substrate. In someembodiments, the metal region may comprise germanium.

At 304, the platen is rotated around an axis of rotation. Rotation ofthe platen causes the semiconductor substrate to rotate around the axisof rotation.

At 306, a slurry comprising an oxidant and an etching inhibitor having anitrogen-oxide (N-oxide) compound is provided onto the common interface.

At 308, a chemical mechanical polishing pad is brought into contact withthe rotating semiconductor substrate. Upon being brought into contactwith the polishing pad, the semiconductor substrate is polishing,thereby removing excess metal from semiconductor substrate. Since theslurry, which comprises an etching inhibitor, is used in the polishingprocess the chemical mechanical polishing process is performed with ahigh metal to oxide removal selectivity and a low rate of metal recessformation

FIG. 4 illustrates some additional embodiments of a disclosed chemicalmechanical polishing slurry manufacturing and delivery system 400.

The chemical mechanical polishing slurry manufacturing and deliverysystem 400 comprises a slurry manufacturing tank 402 configured tomanufacture slurry, which is then packaged into a slurry container 408.The slurry manufacturing tank 402 is connected to an oxidant source 404and to an etching inhibitor source 406. The oxidant source 404 isconfigured to provide an oxidant to the slurry manufacturing tank 402.In various embodiments, the oxidant may comprise hydrogen peroxide,potassium peroxydisulfate, ammonium peroxydisulfate, sodiumperoxydisulfate, potassium peroxymonosulfate, peracetic acid, ortert-butyl hydrogen peroxide.

The etching inhibitor source 406 is configured to provide an etchinginhibitor to the slurry manufacturing tank 402, comprising anitrogen-oxide compound having a chemical formula of R1R2R3N⁺—O⁻,wherein R1 is a first substituent, R2 is a second substituent, and R3 isa third substituent. In various embodiments, the substituents, R1-R3,may comprise different chemicals or the same chemicals. For example, thesubstituents, R1-R3, may comprise chains of carbon alkyl substituent, asdescribed above. In some embodiments, the slurry manufacturing tank 402may comprise additional inlets configured to provide de-ionized waterand/or abrasives to the slurry manufacturing tank 402, which aresubsequently introduced into the slurry.

The slurry packaged within the slurry container 408 is configured to betransported into a day tank 410 comprised within a slurry deliverysystem. In the slurry delivery system, the slurry is provided by way ofa transport piping 412 from the day tank 402 to one or more valvemanifold boxes 414. The valve manifold boxes 414 are configured toselectively provide the slurry from the transport piping 412 to achemical mechanical polishing (CMP) tool 416, when the CMP tool 416 isoperated to perform a chemical mechanical polishing of a semiconductorsubstrate.

In some embodiments, a re-circulation transport piping 418 is configuredto return slurry that has not been provided to the CMP tool 416 from theone or more valve manifold boxes 414 to the slurry day tank 410. Theslurry day tank 410 is configured to mix the unused slurry with newslurry to maintain a slurry having a high metal to oxide selectivitywith a low rate of metal recess formation. The nitrogen-oxide compoundfurther increases the life of the slurry within the slurry day tank 410.For example, in some embodiments, the slurry may be reused for at timeperiod of at least six months.

FIGS. 5A-5G illustrate some alternative embodiments of chemicalstructures of a disclosed slurry with an etching inhibitor comprising anitrogen-oxide compound.

FIG. 5A illustrates a disclosed slurry comprising pyridine N-oxidecompound 500. The pyridine-N-oxide compound 500 is a heterocycliccompound with the formula C₅H₅NO that is a product of the oxidation ofpyridine (C₅H₅N).

FIG. 5B illustrates a disclosed slurry comprising a2,2,6,6-Tetramethylpiperidine-1-oxyl (i.e., TEMPO) compound 502. The2,2,6,6-Tetramethylpiperidine-1-oxyl compound 502 is a chemical compoundwith the formula (CH₂)₃(CMe₂)₂NO.

FIG. 5C illustrates a disclosed slurry comprising a N-methylmorpholineN-oxide compound 504. The N-methylmorpholine N-oxide (NMO) compound 504is a chemical compound with a formula C₅H₁₁NO₂.

FIG. 5D illustrates a disclosed slurry comprising a5,5-dimethyl-1-pyrroline N-oxide compound 508. The5,5-dimethyl-1-pyrroline N-oxide compound 508 is a chemical compoundwith the formula C₆H₁₁NO.

FIG. 5E illustrates a disclosed slurry comprising a trimethylamineN-oxide compound 510. The trimethylamine N-oxide compound 510 is anorganic compound with a formula (CH₃)₃NO.

FIG. 5F illustrates a disclosed slurry comprising a quinoline N-oxidecompound 512. The quinoline N-oxide compound 512 is a chemical compoundwith the formula C₉H₇NO.xH₂O

FIG. 5G illustrates a disclosed slurry comprising a 2-mercaptopyridineN-oxide compound 514. The 2-mercaptopyridine N-oxide compound 514 is achemical compound with a formula C₅H₅NOS

FIG. 6 illustrates a flow chart of some embodiments of a method 600 offorming a silicon germanium (SiGe) fin field effect transistor (FinFET)transistor using a chemical mechanical polishing process with a highgermanium to oxide removal selectivity and a low rate of germaniumrecess formation.

At 602, a semiconductor substrate is selectively etched to form one ormore first trenches within the semiconductor substrate. The one or morefirst trenches are recesses within the semiconductor substrate.

At 604, an oxide is formed in the one or more first trenches.

At 606, the semiconductor substrate is selectively etched to removesilicon to form one or more second trenches. The one or more secondtrenches extend into the semiconductor substrate as recesses atpositions between the oxide formed in the one or more first trenches (at604).

At 608, one or more channel regions are formed by depositing germanium,silicon germanium, and/or a III-V semiconductor material in the one ormore second trenches. In various embodiments, the III-V semiconductormaterial may be formed by combining a group III element (e.g., Al, Ga,and/or In) with a group V element (e.g., N, P, As, and/or Sb). In someembodiments, the resulting III-V semiconductor material may comprisegallium arsenide (GaAs), indium phosphide (InP), gallium phosphide(GaP), gallium arsenide phosphide (GaAsP), aluminum gallium arsenide(AlGaAs), or gallium nitride (GaN), for example.

At 610, a chemical mechanical polishing (CMP) process is performed usinga CMP slurry comprising an oxidant and an etching inhibitor having anitrogen-oxide compound. The nitrogen oxide compound may have a chemicalformula of R1R2R3N⁺—O⁻, wherein R1 is a first substituent, R2 is asecond substituent, and R3 is a third substituent. The etching inhibitorprovides for a high germanium or III-V semiconductor material to oxideselectivity with a low rate recess formation in the germanium or theIII-V semiconductor material.

At 612, a selective etch is performed to etch back the oxide to generateone or more three-dimensional fins comprising the channel regions.

At 614, source and drain regions are formed at opposite ends of the oneor more channel regions.

At 616, one or more gate regions are formed above the channel regions atpositions between the source and drain regions.

FIGS. 7A-7F illustrate cross-sectional views of some embodiments of anexemplary semiconductor substrate, whereon a method of forming a SiGeFinFET according to method 600 is implemented. Although FIGS. 7A-7F aredescribed in relation to method 600, it will be appreciated that thestructures disclosed in FIGS. 7A-7F are not limited to such a method.Rather, it will be appreciated that the illustrated structures of FIGS.7A-7F provide for a structural description of a SiGe FinFET that is ableto stand alone independent of a method.

FIG. 7A illustrates some embodiments of a cross-sectional view 700corresponding to 602-604. As shown in cross-sectional view 700, asemiconductor substrate 702 is selectively etched to form a firstplurality of trenches. The first plurality of trenches extend from a topsurface of the semiconductor substrate 702 to a position within thesemiconductor substrate 702 and leave a plurality of silicon pillarsextending out from the semiconductor substrate 702. An oxide 704 orother dielectric material is then formed within the plurality oftrenches. In some embodiments, the oxide 704 may comprise silicondioxide (SiO₂).

FIG. 7B illustrates some embodiments of a cross-sectional view 706corresponding to 606. As shown in cross-sectional view 706, thesemiconductor substrate 702 is selectively etched to remove silicon toform a second plurality of trenches 708.

FIG. 7C illustrates some embodiments of a cross-sectional view 710corresponding to 608. As shown in cross-sectional view 710, germaniumand/or a III-V semiconductor material 712 is deposited in the secondplurality of trenches 708 to form a plurality of channel regions.

FIG. 7D illustrates some embodiments of a cross-sectional view 714corresponding to 610. As shown in cross-sectional view 710, a chemicalmechanical polishing (CMP) process is performed using a CMP slurryhaving a etching inhibitor that provides for a high germanium oxideselectivity with a low rate of recess formation in the germanium. Thechemical mechanical polishing process removes excess material from thesubstrate. In some embodiments, the chemical mechanical polishingprocess forms a planar substrate along CMP line 716. Since the slurryprovides for a high germanium oxide selectivity, germanium and/or theIII-V semiconductor material 712 is removed from the semiconductorsubstrate at a higher rate than the oxide 704, resulting in asubstantially flat surface on the top of the semiconductor substrate.

FIG. 7E illustrates some embodiments of a cross-sectional view 718corresponding to 612. As shown in cross-sectional view 718,three-dimensional fins 720 are formed by selectively etching back theoxide 704. The three-dimensional fins comprise germanium and/or theIII-V semiconductor material.

FIG. 7F illustrates some embodiments of a three-dimensional view 722corresponding to 614-616. As shown in three-dimensional view 722, a gateregion 724 is formed at a position overlying the three-dimensional fins720. Source and drain regions 726 are formed within thethree-dimensional fins 720 at opposite sides of the gate region 724. Insome embodiments, the source and drain regions 726 may be formed byselectively etching the three-dimensional fins 720 to form source anddrain recesses, and subsequently performing an epitaxial growth to formthe source and drain regions 724 within the recesses. Although, FIG. 7Fillustrates a FinFET device having two gates, it will be appreciatedthat in alternative embodiments, a disclosed finFET may be formed tohave any number of gates.

FIG. 8 is a chart 800 showing the germanium to oxide selectivity of someembodiments of a disclosed slurry with an etching inhibitor. The firstrow of the chart 800 describes a first slurry composition that does notcontain a nitrogen oxide etching inhibitor, such that comparison of rows2-5 to the first row indicates the effect of the nitrogen-oxide etchinginhibitor.

The first row of the chart 800 illustrates a first slurry compositionwithout a nitrogen-oxide etching inhibitor. The first slurry compositionconsist of 2,000 ppm colloidal silica, 1,000 ppm H₂O₂, 200 ppmpolyethylene glycol, and has a pH level of 3. The first slurrycomposition provides for a rate of germanium removal of approximately2,200 angstroms/minute, and for a rate of oxide removal of approximately80 angstroms/minute. Therefore, the resulting germanium to oxideselectivity is 27.5 and a germanium recess is formed having a depth of835 angstroms.

The second row of the chart 800 illustrates a second slurry compositioncomprising a nitrogen-oxide etching inhibitor. The second slurrycomposition comprises 2,000 ppm colloidal silica, 1,000 ppm H₂O₂, 2,000ppm 2-mercaptopyridine N-oxide, 200 ppm polyethylene glycol, and has apH level of 3. The second slurry composition provides for a rate ofgermanium removal of approximately 1845 angstroms/minute, and for a rateof oxide removal of approximately 28 angstroms/minute. Therefore, theresulting germanium to oxide selectivity is 65 and a germanium recess isformed having a depth of 100 angstroms.

The third row of the chart 800 illustrates a third slurry compositioncomprising a nitrogen-oxide etching inhibitor. The third slurrycomposition comprises 2,000 ppm colloidal silica, 30,000 ppm ammoniumperoxydisulfate, 5,000 ppm 4-methylpyridine N-oxide, 500 ppmpolyethylene glycol, and has a pH level of 3. The third slurrycomposition provides for a rate of germanium removal of approximately1,245 angstroms/minute, and for a rate of oxide removal of approximately15 angstroms/minute. Therefore, the resulting germanium to oxideselectivity is 83 and a germanium recess is formed having a depth of 35angstroms.

The fourth row of the chart 800 illustrates a fourth slurry compositioncomprising a nitrogen-oxide etching inhibitor. The fourth slurrycomposition comprises 2,000 ppm colloidal silica, 8,000 ppm tert-butylhydrogen peroxide, 3,000 ppm N-methylmorpholine N-oxide, 500 ppmpolyethylene glycol, and has a pH level of 6. The fourth slurrycomposition provides for a rate of germanium removal of approximately1,856 angstroms/minute, and for a rate of oxide removal of approximately21 angstroms/minute. Therefore, the resulting germanium to oxideselectivity is 88 and a germanium recess is formed having a depth of 48angstroms.

The fifth row of the chart 800 illustrates a fifth slurry compositioncomprising a nitrogen-oxide etching inhibitor. The fifth slurrycomposition comprises 8,000 ppm tert-butyl hydrogen peroxide, 3,000 ppmN-methylmorpholine N-oxide, 500 ppm polyethylene glycol, and has a pHlevel of 10. The fifth slurry composition is free of abrasive particles.The fifth slurry composition provides for a rate of germanium removal ofapproximately 656 angstroms/minute, and for a rate of oxide removal ofapproximately 3 angstroms/minute. Therefore, the resulting germanium tooxide selectivity is 218 and a germanium recess is formed having a depthof 25 angstroms.

It will be appreciated that while reference is made throughout thisdocument to exemplary structures in discussing aspects of methodologiesdescribed herein, those methodologies are not to be limited by thecorresponding structures presented. Rather, the methodologies andstructures are to be considered independent of one another and able tostand alone and be practiced without regard to any of the particularaspects depicted in the Figs.

Also, equivalent alterations and/or modifications may occur to one ofordinary skill in the art based upon a reading and/or understanding ofthe specification and annexed drawings. The disclosure herein includesall such modifications and alterations and is generally not intended tobe limited thereby. For example, although the figures provided hereinare illustrated and described to have a particular doping type, it willbe appreciated that alternative doping types may be utilized as will beappreciated by one of ordinary skill in the art.

In addition, while a particular feature or aspect may have beendisclosed with respect to one of several implementations, such featureor aspect may be combined with one or more other features and/or aspectsof other implementations as may be desired. Furthermore, to the extentthat the terms “includes”, “having”, “has”, “with”, and/or variantsthereof are used herein, such terms are intended to be inclusive inmeaning—like “comprising.” Also, “exemplary” is merely meant to mean anexample, rather than the best. It is also to be appreciated thatfeatures, layers and/or elements depicted herein are illustrated withparticular dimensions and/or orientations relative to one another forpurposes of simplicity and ease of understanding, and that the actualdimensions and/or orientations may differ from that illustrated herein.

Therefore, the present disclosure relates to a chemical mechanicalpolishing (CMP) slurry composition that provides for a high metal todielectric material selectivity along with a low rate of metal recessformation.

In some embodiments, the present disclosure relates to a chemicalmechanical polishing (CMP) slurry composition configured to provide fora high metal to oxide removal selectivity with a low rate of metalrecess formation. The CMP slurry composition comprises an oxidant havinga compound having one or more oxygen molecules. The CMP slurrycomposition further comprises an etching inhibitor having nitrogen-oxidecompound having a chemical formula of R1R2R3N⁺—O⁻, wherein N⁺ comprisesa nitrogen molecule, O⁻ comprises an oxygen molecule, R1 is a firstsubstituent, R2 is a second substituent, and R3 is a third substituent.

In other embodiments, the present disclosure relates to a chemicalmechanical polishing (CMP) slurry composition. The CMP slurrycomposition comprises an oxidant comprising a compound having one ormore oxygen molecules and an etching inhibitor configured to provide fora III-V semiconductor material to dielectric material removalselectivity greater than or equal to 30. The etching inhibitor comprisesa nitrogen-oxide compound having a chemical formula of R1R2R3N⁺—O⁻,wherein N⁺ comprises a nitrogen molecule, O⁻ comprises an oxygenmolecule, R1 comprises a first substituent having 1-20 carbon alkylsubstituents disposed within a parent-chain, a side-chain, or as cyclicsubstituents, R2 comprises a second substituent having 1-20 carbon alkylsubstituents disposed within a parent-chain, a side-chain, or as cyclicsubstituents, and R3 comprises a third substituent, having 0-10 carbonalkyl substituents disposed within a parent-chain, a side-chain, or ascyclic substituents.

What is claimed is:
 1. A chemical mechanical polishing (CMP) slurrycomposition configured to provide for a high metal to dielectricmaterial removal selectivity with a low rate of metal recess formation,consisting of: an oxidant comprising a peroxide; an etching inhibitorconfigured to reduce a removal rate of a metal relative to an oxide, soas to provide the CMP slurry composition with a metal-to-oxide etchingselectivity of greater than or equal to approximately 60-to-1, whereinthe etching inhibitor comprises a nitrogen-oxide compound having achemical formula of R1R2R3N⁺—O⁻, wherein N⁺ comprises a nitrogenmolecule, O⁻ comprises an oxygen molecule, R1 is a first substituent, R2is a second substituent, and R3 is a third substituent; a solvent; andone or more abrasive particles.
 2. The slurry composition of claim 1,wherein the etching inhibitor comprises2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) and is configured to reducea removal rate of silicon germanium relative to a removal rate of anoxide.
 3. The slurry composition of claim 1, wherein the oxidantcomprises a concentration having a range of between approximately 10 ppmand 50,000 ppm.
 4. The slurry composition of claim 1, wherein the firstsubstituent, R1, and the second substituent, R2, have 1-20 carbon alkylsubstituents disposed as cyclic substituents; and wherein the thirdsubstituent, R3, has 0-10 carbon alkyl substituents disposed as cyclicsubstituents.
 5. The slurry composition of claim 1, wherein the etchinginhibitor comprises pyridine N-oxide, 4-methylpyridine N-oxide,N-methylmorpholine N-oxide, 5,5-dimethyl-1-pyrroline N-oxide,trimethylamine N-oxide, quinoline N-oxide, or 2-mercaptopyridineN-oxide.
 6. The slurry composition of claim 1, wherein the etchinginhibitor comprises a concentration having a range of betweenapproximately 10 ppm and 50,000 ppm.
 7. The slurry composition of claim1, further comprising an abrasive including colloidal silica, fumedsilica, aluminum oxide, or a silica shell based composite submicronparticle.
 8. The slurry composition of claim 1, wherein slurrycomposition comprises a pH level having a range of between approximately1 and
 10. 9. The slurry composition of claim 1, further comprising: asurfactant comprising having a concentration in a range of betweenapproximately 200 ppm and approximately 500 ppm.
 10. The slurrycomposition of claim 9, wherein the oxidant is ammonium peroxydisulfate,the etching inhibitor is 4-methylptridine N-oxide, and the surfactant ispolyethylene glycol.
 11. The slurry composition of claim 9, wherein theoxidant is tetr-butyl hydrogen peroxide, the etching inhibitor isN-methylmorpholine N-oxide, and the surfactant is polyethylene glycol.12. The slurry composition of claim 11, wherein the slurry compositionis devoid of abrasive particles.
 13. A chemical mechanical polishing(CMP) slurry composition, consisting of: an oxidant comprising potassiumperoxydisulfate, ammonium peroxydisulfate, sodium peroxydisulfate,potassium peroxymonosulfate, peracetic acid, or tert-butyl hydrogenperoxide; an etching inhibitor configured to reduce a removal rate ofsilicon germanium relative to an oxide, wherein the etching inhibitorconsists of pyridine N-oxide, 4-methylpyridine N-oxide,N-methylmorpholine N-oxide, 5,5-dimethyl-1-pyrroline N-oxide,trimethylamine N-oxide, quinoline N-oxide, or 2-mercaptopyridineN-oxide; and de-ionized water.
 14. The slurry composition of claim 13,further comprising: a surfactant comprising having a concentration ofbetween approximately 200 and 500 ppm.
 15. The slurry composition ofclaim 14, wherein the oxidant is ammonium peroxydisulfate, the etchinginhibitor is 4-methylptridine N-oxide, and the surfactant ispolyethylene glycol.
 16. The slurry composition of claim 14, wherein theoxidant is tetr-butyl hydrogen peroxide, the etching inhibitor isN-methylmorpholine N-oxide, and the surfactant is polyethylene glycol.17. The slurry composition of claim 16, wherein the slurry compositionis devoid of abrasive particles.
 18. The slurry composition of claim 13,wherein the etching inhibitor comprises a concentration having a rangeof between approximately 10 ppm and 50,000 ppm.
 19. The slurrycomposition of claim 13, further comprising an abrasive including one ormore of: colloidal silica, fumed silica, aluminum oxide, and a silicashell based composite submicron particle.
 20. A chemical mechanicalpolishing (CMP) slurry composition configured to provide for a highmetal to dielectric material removal selectivity with a low rate ofmetal recess formation, consisting of: an oxidant comprising a compoundhaving one or more oxygen molecules; and an etching inhibitor configuredto reduce a removal rate of silicon germanium relative to an oxide,wherein the etching inhibitor consists of pyridine N-oxide,4-methylpyridine N-oxide, N-methylmorpholine N-oxide,5,5-dimethyl-1-pyrroline N-oxide, trimethylamine N-oxide, quinolineN-oxide, or 2-mercaptopyridine N-oxide; de-ionized water; and one ormore abrasive particles.